Apparatus and method for loading a bag train

ABSTRACT

The preferred embodiment is an apparatus for taking up two carrier tapes ( 52   a   , 52   b ) of a bag train incorporating a succession of imbricated packaging bags ( 51    a,    51    b,    51    c ) that comprises two spools ( 12   a   , 12   b ), one for taking up each carrier tape and a differential gear unit ( 20 ) positioned between the spools. In use the apparatus is removably connected to the bag loader, e.g. by snap-on fitting, in a way that the differential gear unit is driven by a shaft ( 112 ) of the bag loader and rotates the spools to take up the respective supply tapes with equal tension. The spools are positioned coaxially in the apparatus. Also disclosed is a method of loading a bag chain on a bag loader using such an apparatus.

The present invention relates to an apparatus for taking up tapes onwhich a succession of imbricated bags, suitable for packaging, arecarried. For example, meat cuts, or poultry may be loaded into the bagsas they are removed from the tapes by a bag loader.

The use of taped imbricated bags has been known for many years and themost commonly available form of these bags uses two separate adhesivecarrier tapes which have an imbricated array of the bags placed on thetapes in such a way that the adhesive face of each tape contacts theexposed part of each bag in the imbricated array. Normally the lead bagof the array is attached to the tapes by its end at which the mouth isdisposed.

U.S. Pat. No. 4,798,412 discloses a bag loader which includes adifferential drive unit which drives two driving shafts onto which acassette can be loaded. The cassette contains two tape winding spoolsone for each tape of a chain of bags. The differential drive unit of thebag loader can wind up the tapes onto the spools with equal tension.However, the drive unit of the bag loader is complicated and requiresmany components because of the two shafts which must extend from the bagloader with axes which are parallel but not coaxial. Furthermore, such acassette is required to hold the spools in place and is necessarilyquite large and bulky as the spools are positioned one beside the otherto allow connection to the two shafts of the drive unit of the bagloader.

GB 2,064,477 discloses a bag loader which includes a differential driveunit which drives two tape winding spools which are positioned coaxiallywith one another. The differential drive gear is permanently attached tothe bag loader (integral therewith). Thus, to load a succession ofimbricated taped bags, the two used tapes need to be removed from thespools by an operator who also needs to connect the new tapes to thesame empty spools in the bag loader.

The present invention provides an apparatus for taking up a successionof imbricated packaging bags carried by a pair of carrier tapes, saidapparatus comprising: two carrier tape winding spools positionedcoaxially with one another; and a differential gear unit positionedbetween said spools, said differential gear unit being adapted to be, inuse, removably connectable to a shaft of a bag loader whereby twocarrier tapes can be wound up on said spools with equal tension.

Thus the bag loader is less complex with only a single driving shaft andthe high number of gears in the differential drive unit of the bagloader are no longer required. The gears of the differential gear unitof the apparatus of the present invention are only required to be usedfor one bag train and thus may be made of cheap materials, for exampleof injection moulded plastics. If the apparatus is to be reusable,harder wearing materials may need to be used. Thus, the next set of bagscan be easily attached without tools and with only one component to fitonto a single shaft of the bag loader.

The apparatus dimensions can be vastly reduced compared to the cassettedimensions when the two spools were positioned side by side within thecassette. This is only possible because of the coaxial positioning ofthe differential gear unit with the spools. This results in a loweringof the cost of the apparatus because of the elimination of the need fora cassette housing or reduction in the bulk of the housing with thecoaxial arrangement and, as the dimensions are less, the thickness ofthe walls for a given rigidity and strength can be reduced. Theincreased cost of the apparatus due to the need to provide it with adifferential drive unit is offset by the reduced amount of materialneeded for the apparatus.

The present invention also provides a method of loading a bag train on abag loader, comprising: taking a bag train incorporating a succession ofimbricated packaging bags on two supply tapes from which they are to beremoved during the loading operation, the supply tapes having lead endsequipped with two tape-winding spools with a differential gear unit ispositioned coaxially between the spools; connecting the differentialgear unit to a shaft of said bag loader; and driving said spools to windup said tapes on said spools with equal tension to bring each of theimbricated bags successively to a loading position where the bag isloaded and separated from the tapes.

The invention will be described by way of example only with reference tothe accompanying drawings in which:

FIG. 1 is a perspective view of a bag train with cassette being loadedon to a bag loader;

FIG. 2 is an exploded view of a cassette of the present invention; and

FIG. 3 is an exploded view of the apparatus for taking up a successionof imbricated packaging bags of the present invention.

FIG. 1 shows schematically how the present invention is employed in useon a bag loader machine 100. A bag train 50 comprises a plurality ofpackaging bags 51 a, 51 b, 51 c arranged in an imbricated way on twoparallel carrier tapes 52 a, 52 b (usually about ½ bag width apart). Thebags 51 a, 51 b, 51 c are attached to the tapes 52 a, 52 b by adhesive.The end of the tapes 52 a, 52 b are positioned in a cassette 10. Thecassette 10 is loaded by hand, without tools, on to a shaft 112 of thebag loader 100 so that the unit is adapted to be, in use, removablyconnectable to the shaft. The adaptation may be by way of a snap-onfitting, a butterfly nut, an over center buckle etc. Any way ofattaching the unit by hand, without the use of tools, so that littletime or skill is required can be used. Although a door to protect thecassette 10 is shown in the figure, in practice this may not benecessary. The shaft 112 is rotated by motor 110. The shaft 112 engageswith the cassette 10 and drives the internal workings of the cassette totake up the tapes 52 a, 52 b. On taking up of the tapes 52 a, 52 b thesuccession of bags 51 a, 51 b, 51 c are brought closer to the bag loadermachine 100. As the tapes are taken up successive bags 51 a, 51 b, 51 ccan be removed from the tapes 52 a, 52 b and filled.

During drawing of the bags 51 a, 51 b, 51 c towards the bag loader 100,it is necessary to keep the tension in the two tapes 52 a, 52 b equal sothat the bag openings, usually directed in the direction of advancement,remain in the same orientation to the bag loader 100 (i.e. usuallyparallel to the bag loader) such that the bags may be removed from thetapes automatically. In the present invention this is done by use of thecassette 10 which ensures that the tapes 52 a, 52 b, as they are drawnin towards the bag loader around rollers or stationary pins 54 a, 54 b,are kept in equal tension. This is achieved by the internal workings ofthe cassette 10 which are illustrated in FIG. 2.

The way in which the cassette 10 takes up the carrier tapes 52 a, 52 bwith equal tension will now be described with reference to FIG. 2. Thecassette 10 comprises two carrier tape winding spools 12 a, 12 b uponwhich the tapes 52 a, 52 b of the bag train 50 are to be wound. Thespools 12 a, 12 b are enclosed in a housing of the cassette 10comprising first and second components 14 a, 14 b which can, forexample, snap fit together. A slot 15 formed in the first housingcomponent 14 a allows entry of the tapes 52 a, 52 b into the housing andthereby onto spool 12 a for one tape 52 a and spool 12 b for the othertape 52 b. Two slots may be provided, one for entry of each tape 52 a,52 b. If those slots are positioned as far apart as the tapes are apartwhen attached to the bags, no rollers or pins 54 a, 54 b are required.The tapes 52 a, 52 b are attached to the spools 12 a, 12 b in anyconvenient way, for example through a hole in the outer flange of thespool and held in place by a pin inserted in the hole from the outside.The tapes 52 a, 52 b are wound around the spools 12 a, 12 b in the samedirection.

The spools 12 a, 12 b are positioned coaxially with one another insideof the housing. Each of the spools 12 a, 12 b is depicted as having acentral cut out 13 though this is not necessarily the case. In fact,only one of the spools 12 a, 12 b will require a central cut out 13 sothat the shaft 112 of the bag loader can access a differential gear unit20 positioned between and coaxially with the spools 12 a, 12 b. Theshaft 112 passes through the housing 14 b in a cut out 16, through thecentral cut out 13 of spool 12 b to mesh with a mating hole 22 in a core21 of the differential gear unit 20. Thus, the spools 12 a, 12 b andcore 21 of the differential gear unit are coaxial with the shaft 112 ofthe bag loader when the cassette is loaded on the bag loader.

Mounted on the core 21 is at least one bevel pinion 24. In the preferredembodiment there are four bevel pinions 24 positioned symmetricallyaround the outside of the core 21. The bevel pinions 24 are mounted tothe core such that they can freely rotate around an axis perpendicularto the longitudinal axis of mating hole 22.

The differential gear unit 20 is held substantially coaxially with saidspools 12 a, 12 b by being positioned in recesses in the surfaces of thespools facing each other so that the spools can be positioned closetogether, possibly even touching. The action of engaging the cassettewith the shaft 112 may serve to axially align the spools 12 a, 12 b andthe core 21 of the differential gear unit and to hold them together.Alternatively, the spools and differential gear unit may be designed tosnap fit together (or otherwise held together) without the aid of thecassette 10 or shaft 112 so that the shaft 112 only engages with thedifferential gear unit 20.

Each of the spools 12 a, 12 b is provided with an integrally mouldedbevel gear 26 (in the recess) which, when the cassette 10 is assembled,faces the other of said spools 12 a, 12 b and meshes with the bevelpinions 24. In this way, if equal tension is present in the tapes 52 a,52 b and the shaft 112 of the bag loader rotates the core 21, the twospools 12 a, 12 b will be rotated at the same rate as the bevel pinions24 will not rotate around their axis of rotation but the whole core andspool assembly will rotate at the same rate around the longitudinal axisof the shaft 112. However, if tension in one of the tapes 52 a, 52 bdecreases, the spool 12 a, 12 b on which that tape is wound will rotatefaster than the other spool. This happens because the bevel pinions 24will begin to rotate until the tension in the tapes 52 a, 52 b woundaround their respective spools 12 a, 12 b is equalised. In this way itis possible to maintain the bag train 50 in an orientation such thateach successive imbricated bag 51 a, 51 b, 51 c will arrive at the bagloader in the perfect orientation for removal from the tapes 52 a, 52 bas the tapes 52 a, 52 b are taken up by the spools 12 a, 12 b of thecassette 10.

As will be apparent, the cassette housing is not required for thecorrect functioning of the invention as shown in FIG. 3. The spools anddrive unit could be individually directly assembled onto the shaft 112or could be assembled on to the shaft 112 as one and be snap fitted orotherwise fixed together for convenience. A lip and flange on the core21 to engage through a central through hole of the spools would be asatisfactory way of seeing to this.

The cassette housing components 14 a, 14 b, spools 12 a, 12 b and theparts of the differential gear unit may all be formed by injectionmoulding of plastics material. This is cheap and the thus producedcomponents easily have the durability to last for the entire bag trainwhich can comprise several hundred bags.

It is envisaged that the cassette will be stored, for example duringshipping, with the leading part of each of the tapes connected to therespective spool so that the entire bag chain 50 may be loaded onto theloader easily without first having to connect the tapes 51 a, 52 b ontothe spools 12 a, 12 b.

The cassette 10 can be re-usable. In use, the machine operator wouldattach the next bag train to the spools of a spare cassette whilst themachine is still working using another bag train. Once that other bagtrain is finished, the operator can substitute the old cassette for thespare one and restart the machine.

The present invention has been described by way of example only andvariations are possible. In particular, as described above, the cassette10 is not necessary for the functioning of the invention as shown inFIG. 3. The construction of the housing of the cassette could be varied.

1. An apparatus for taking up a succession of imbricated packaging bagscarried by a pair of carrier tapes, said apparatus comprising: twocarrier tape winding spools positioned coaxially with one another; and adifferential gear unit positioned between said spools, said differentialgear unit being adapted to be, in use, removably connectable to a shaftof a bag loader whereby two carrier tapes can be wound up on said spoolswith equal tension.
 2. An apparatus according to claim 1, wherein saidspools each have a recess in a surface which faces the other spool andwherein said differential gear unit is positioned in said recesses. 3.An apparatus according to claim 1 or 2, wherein each of said spools isintegrally formed with a bevel gear coaxial with said spool.
 4. Anapparatus according to claim 3, wherein said differential gear unitcomprises a core and at least one satellite pinion gear attached to saidcore and positioned to mesh with each bevel gear.
 5. An apparatusaccording to claim 4 wherein said core comprises a mating hole formating with a shaft of a bag loader.
 6. An apparatus according to anyone of the preceding claims, wherein said spools and differential gearunit are positioned in a cassette housing.
 7. An apparatus according toany one of the preceding claims, wherein said differential gear unit isremovably connectable to said shaft without the use of tools.
 8. A bagtrain comprising a succession of imbricated packaging bags carried by apair of parallel carrier tapes and an apparatus according to any one ofthe preceding claims.
 9. A bag train according to claim 8 wherein endsof said carrier tapes are each connected to a spool of said apparatus.10. A method of loading a bag train on a bag loader, comprising: takinga bag train incorporating a succession of imbricated packaging bags ontwo supply tapes from which they are to be removed during the loadingoperation, the supply tapes having lead ends equipped with twotape-winding spools with a differential gear unit is positionedcoaxially between the spools; connecting the differential gear unit to ashaft of said bag loader; and driving said spools to wind up said tapeson said spools with equal tension to bring each of the imbricated bagssuccessively to a loading position where the bag is loaded and separatedfrom the tapes.